The 2011 budget request for NASA has generated much debate about the right course for America in space. You have raised the issue of safety as an indispensable component of any new plan for NASA, and we wish to express our appreciation for your leadership in ensuring that safety is at the center of this debate.

Both as astronauts and as citizens who care passionately about the future of human spaceflight, we write today to communicate our views on this critical issue.

Let us be clear: we believe that that the private sector, working in partnership with NASA, can safely develop and operate crewed space vehicles to low Earth orbit. We have reached this conclusion for a number of reasons:

A simpler mission - Two fundamental drivers of safety are the simplicity of the system and the difficulty of the mission. By focusing on a simple spacecraft intended only to service low Earth orbit, commercial providers will avoid both the complexity of the Space Shuttle and the more extreme environments encountered by vehicles designed for exploration beyond. US industry has almost fifty years of experience with Earth Orbit operations, and experienced companies, such as the established firms whose engineers developed Mercury, Gemini, the Space Shuttle, and the International Space Station, will contribute those decades of knowledge to a commercial crew initiative.

Demonstrated reliability - Because safety predictions can be an imprecise art, an important additional factor for the safety of human spaceflight is demonstrated reliability. Demonstrated reliability is a beneficial factor for safety. The Atlas 5 has had a perfect record of over 20 successful flights in a row, and Delta 4 has over a dozen. The Falcon 9 has already shown its ability to reach orbit and will have had numerous test flights before putting humans aboard. Under the new NASA program, no crewmember will ever fly on an unproven rocket.

Trust of the national security community - The Air Force routinely depends upon commercial rockets to launch invaluable satellites that are critical to national security. The lives of the men and women in our armed forces depend on these launches. And every time a commercial rocket launches these national security satellites, or for that matter NASA science or cargo missions, these vehicles further prove out their systems and provide valuable data relevant to safe operations when carrying astronaut crews.

NASA will exercise strong oversight - NASA's leadership has made clear that NASA will exercise strong insight and oversight throughout all phases of the Commercial Crew program. Through existing programs such as COTS and CCDev, industry has already begun working with NASA to design and develop vehicles that meet or exceed the safety levels stipulated in NASA's current human rating standards document, known as NPR 8705.2B. Industry is now working with NASA on a human-rating plan that will optimize safety and specify NASA insight and oversight, and we are confident NASA will finalize these human rating requirements in a timely fashion.

A shared vision - Commercial space workers and managers care about safety just as much as those working at NASA. Many commercial space workers have come from our Nation's space program and have deep historical knowledge and understanding of the safety issues for human spaceflight, and former astronauts are deeply involved in the engineering, manufacture, and eventual operations of commercial crew vehicles. As members of the space community, they care strongly about safety, and they know that their goals of opening up the space frontier will not be realized without safe and reliable flights.

In conclusion, an analogue from earlier in the Space Age, of similar scope to Commercial Crew, may serve as a useful historical precedent. Almost 40 years ago, NASA's Gemini program human-rated a launch vehicle and developed a capsule for about $2.5-$3.0 billion in today's dollars, and each Gemini flight was completed safely. We believe it is reasonable that the private sector can also develop safe and simple crew transportation, especially with the benefit of almost a half-century of experience and safety improvements since Gemini.

The success of NASA's proposed Commercial Crew program is critical. By allowing the private sector to take on the transportation of crew to low Earth orbit, NASA will finally be able to direct its resources and focus on human exploration beyond, and we strongly feel this direction for the agency is the right one.